Hemolytic anemia

Alternative names
Anemia - hemolytic

Definition
Hemolytic anemia is a condition of an inadequate number of circulating red blood cells (anemia), caused by premature destruction of red blood cells. There are a number of specific types of hemolytic anemia which are described individually.

Causes, incidence, and risk factors
Hemolytic anemia occurs when the bone marrow is unable to compensate for premature destruction of red blood cells by increasing their production. When the marrow is able to compensate, anemia does not occur.

There are many types of hemolytic anemia, which are classified by the location of the defect. The defect may be in the red blood cell itself (intrinsic factor), or outside the red blood cell (extrinsic factor).

Causes of hemolytic anemia include infection, certain medications, autoimmune disorders, and inherited disorders. Types of hemolytic anemia include:

     
  • Sickle-cell anemia  
  • Paroxysmal nocturnal hemoglobinuria  
  • Hemoglobin SC disease  
  • Hemolytic anemia due to G6PD deficiency  
  • Hereditary elliptocytosis  
  • Hereditary spherocytosis  
  • Hereditary ovalocytosis  
  • Idiopathic autoimmune hemolytic anemia  
  • Non-immune hemolytic anemia caused by chemical or physical agents  
  • Secondary immune hemolytic anemia  
  • Thalassemia

Symptoms

     
  • Chills  
  • Fatigue  
  • Pale color  
  • Shortness of breath  
  • Rapid heart rate  
  • Yellow skin color (jaundice)  
  • Dark urine  
  • Enlarged spleen

Signs and tests
These are tests for hemolysis (red blood cell destruction). There are specific tests which identify the specific types of hemolytic anemia. They are performed after hemolysis has been established.

     
  • Elevated indirect bilirubin levels  
  • Low serum haptoglobin  
  • Hemoglobin in the urine  
  • Hemosiderin in the urine  
  • Increased urine and fecal urobilinogen  
  • Elevated absolute reticulocyte count  
  • Low red blood cell count and hemoglobin  
  • Elevated serum LDH

Direct measurement of the red cell life span by isotopic tagging techniques shows a decreased life span.

This disease may also alter the following test results depending on the specific cause:

     
  • Uric acid  
  • TIBC  
  • RBC indices  
  • Protein electrophoresis - serum  
  • Potassium test  
  • Platelet count  
  • Peripheral smear  
  • Leukocyte alkaline phosphatase  
  • Serum iron  
  • Hematocrit  
  • Ferritin  
  • Febrile or cold agglutinins  
  • Donath-Landsteiner test  
  • Coombs’ test, indirect  
  • Coombs’ test, direct  
  • CBC  
  • Blood differential  
  • AST  
  • 24 hour urine protein

Treatment
Treatment depends upon the type and cause of the hemolytic anemia. Folic acid, iron replacement, and corticosteroids may be used. In emergencies, transfusion of blood may be necessary.

Expectations (prognosis)
The outcome depends upon the type of hemolytic anemia.

Complications
The complications vary with the specific type of hemolytic anemia. Severe anemia can cause cardiovascular collapse. Severe anemias can aggravate pre-existing heart disease, lung disease, or cerebrovascular disease.

Call for an appointment with your health care provider if symptoms of hemolytic anemia develop.

Prevention
There is no known prevention for hemolytic anemia.

Johns Hopkins patient information

Last revised: December 4, 2012
by Janet G. Derge, M.D.

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